Efficacy of a natural mineral complex in North American adults with osteoarthritis of the knee: a randomized double-blind placebo-controlled study

PURPOSE This study evaluated the efficacy of a hydrothermal mineral complex (HMC) supplement in participants with knee osteoarthritis. PATIENTS AND METHODS This was a double-blind, placebo-controlled, 12-week crossover study with 150 participants receiving either placebo or HMC for 4 weeks, with a 4-week washout period. The primary endpoint was WOMAC™ pain, and secondary endpoints were WOMAC™ physical function and stiffness, the 36-Item Short Form Health Survey (SF-36), high-sensitivity C-reactive protein, tumor necrosis factor α, interleukin 6, and safety. RESULTS There were no significant differences in WOMAC™ pain, stiffness, or physical function scores between groups. Within groups, subjects on both HMC and placebo reported improvements (P<0.001) in all WOMAC™ domains. HMC performed significantly better in total SF-36 scores (P=0.05) and physical function (P=0.02), and had improved total physical activity (P=0.06) and social functioning (P=0.09) scores compared with placebo. Within groups, physical function (P=0.01), limitations due to mental health/emotional well-being (P=0.02), bodily pain (P=0.001), and total physical (P=0.003) and mental health scores (P=0.02) improved in participants on HMC, whereas improvements in bodily pain (P=0.001), general health (P=0.01), and total physical activity (P=0.04) were reported in placebo. Subjects on HMC with body mass index (BMI) <25 kg/m2 showed a trend toward decreased pain scores (P=0.10), while pain increased in those administered placebo. Minimal clinically important improvement (MCII) in WOMAC™ pain scores increased from 28% of HMC-administered participants at week 2 to 41% at week 4, and decreased to 37% after 2 weeks of washout. In comparison, 41% of placebo-administered subjects achieved MCII by week 2 and week 4. A 10.4% greater increase in tumor necrosis factor α levels was seen in participants receiving placebo than those receiving HMC (P=0.07). There were no differences between groups in adverse events. CONCLUSION HMC significantly improved physical function and total physical activity, improving the quality of life of participants. HMC was most effective in normal-weight subjects. Increased dosage may be required for North American subjects with BMI >25 kg/m2.